1. Field of the Invention
The present invention relates to a radiation detector, a radiographic imaging device, a radiographic imaging system and a line capacitance adjusting method. The present invention particularly relates to a radiation detector, a radiographic imaging device and a radiographic imaging system for detecting radiographic images, and a line capacitance adjusting method for adjusting the line capacitance of a signal line provided to the radiation detector.
2. Description of the Related Art
Radiation detectors such as Flat Panel Detection elements (FPD), having a radiation sensitive layer disposed above a Thin Film Transistor (TFT) active matrix substrate, and capable of converting radiation such as X-rays directly into digital data, are recently being put into practice. Radiographic imaging devices employing such radiation detectors allow images to be checked in real time, and enable successive radiographic images to be imaged and fluoroscopy (video imaging) to be performed, in contrast to conventional radiographic imaging devices employing X-ray film or imaging plates.
However, in such types of radiographic imaging device, if the radiographic imaging device itself can detect, for example, the start or end of radiation irradiation and irradiance level, connection to a control device for performing control of for example the radiographic imaging device and the radiation source, and connection to a radiation source becomes unnecessary. Accordingly, a simplification of system configuration and simplification of control by an imaging control device is desired.
Japanese Patent Application Laid-Open (JP-A) No. 2005-147958 discloses a radiographic imaging device capable of detecting a radiation irradiation state. This radiographic imaging device includes plural first photoelectric conversion elements, plural switch elements, drive lines, second photoelectric conversion elements and bias lines. Switch elements are connected to the first photoelectric conversion elements. The drive lines transmit signals to switch plural switch elements ON/OFF. The second photoelectric conversion elements are formed above the drive lines. The bias lines are connected to the first photoelectric conversion elements and the second photoelectric conversion elements. The first photoelectric conversion elements and the second photoelectric conversion elements are formed on the same substrate.
Further, JP-A No. 2004-170216 discloses a radiation detection apparatus provided with second pixels for detecting radiation irradiation. This radiation detection apparatus includes a radiation conversion section disposed with plural conversion elements for converting incident radiation into electric signals on a substrate. In the radiation conversion section, the conversion elements are each connected to a signal line via a switch element for electric signal transfer. First pixels for outputting signals for generating an image and the conversion elements are connected directly to the signal lines.
However, in the technology described in JP-A No. 2005-147958 and JP-A No. 170216, the pixels for detecting a state of radiation irradiation and the pixels for detecting a radiographic image respectively output accumulated electric signals. Accordingly, differences in line capacitance consequently occur between each of the signal lines, and line shaped image irregularities occur in radiographic images according to the differences in line capacitance.